Films and fibers having modified ion affinity and hydrophilicity produced through reaction of such substrates with polyoxyalkylene polyaziridines

ABSTRACT

ANTISTATIC PROPERTIES CAN BE IMPARTED TO SYNTHETIC HYDROPHOBIC MATERIALS, CELLULOSIC MATERIALS, AND BLENDS OF CELLULOSIC MATERIALS WITH SYNTHETIC, HYDROPHOBIC MATERIALS BY CONTACTING SAID MATERIALS WITH A SELECTED POLYAZIRIDINE COMPOUND.

United States Patent US. Cl. 8115.7 19 Claims ABSTRACT OF THE DISCLOSUREAntistatic properties can be imparted to synthetic hydrophobicmaterials, cellulosic materials, and blends of cellulosic materials withsynthetic, hydrophobic materials by contacting said materials with aselected polyaziridine compound.

This application is a continuation application of Ser. No. 183,050 filedMar. 28, 1962, now abandoned, which is relied on.

This invention relates to a process for imparting valuable properties tonatural and synthetic materials and to the materials thus formed. Thisinvention further relates to a process for imparting durable antistaticproperties to hydrophobic materials and, more particularly, to a processfor imparting antistatic properties to shaped synthetic hydrophobicmaterials such as films, fibers, yarns, fabrics, and the like, and tothe antistatic materials thus formed. This invention also relates to aprocess for imparting dimensional stability and aflinity for dyestuffsto natural fibers and shaped hydrophobic materials containing naturalfibers.

As more and more uses are found for synthetic materials in the form offilms, fibers, yarns, textiles, etc., it is noted that many of thesematerials have hydrophobic properties and thus have a detrimentaltendency to accumulate static electrical charges. The continuouslyexpanding use of these synthetic hydrophobic materials in themanufacture of all types of garments, curtains, drapes, upholstery,automobile seat covers, and the like, to mention merely a few fields,results in the demand for increasingly better methods for effectivelyeliminating the accumulation of static electrical charges on the shapedmaterials. Furthermore, during the processing and manufacture oftextiles from such synthetic, hydrophobic materials, the accumulation ofstatic electrical charges on the fibers and yarns interferes with thespinning, weaving, knitting, etc., operations, it causes materials toattract lint and soil, and renders more difficult the cutting and sewingoperations. The accumulation of static electricity during the processingof yarns and fibers to form fabrics may also cause spark dischargeswhich constitute a significant hazard in the textile industry. When thetextiles are in the form of garments, the presence of the staticelectrical charges thereon is objectionable in use, since they cause thegarment to cling uncomfortably to the wearer.

Many attempts have been made to obviate the aforesaid ice disadvantagesand prevent the accumulation of static electricity on hydrophobicsynthetic materials by treating these materials with certain chemicalcompounds, commonly referred to as anti-static agents or finishes. Manyof these known antistatic agents, however, are susceptible to removalduring the laundering or dry cleaning of the textile, and sometimes evenby mere rinsing of the textile in water. To obviate this disadvantage,durable antistatic agents have been developed and found elfective, buteven these still have certain objectionable features. Many of the moredurable antistatic agents must be applied under strongly alkalineconditions in order to achieve the desired results in the finishingtreatment, thereby leading to a lack of compatibility with many othercommonly used functional finishes. In many instances, undesirablefeatures are obtained during the finishing process, one of which is thediscoloration of the finished textile. Furthermore, many of these moredurable antistatic agents must be used with a curing agent, whichusually must be present in a critical ratio relative to the treatingsolution, thus leading to a limited bath stability and to difficultiesin controlling the finishing process. Many of these known durableantistatic agents can be cured only at elevated temperatures, thusmaking them unsuitable for use with synthetic hydrophobic fibers havinglow softening points.

Accordingly, it is an object of the present invention to obviate theaforesaid disadvantages presently existing with known antistatic agentsfor hydrophobic materials, and with the processes utilizing such agentsfor imparting antistatic properties to hydrophobic materials, includingobviating the use of alkaline catalysts or the addition of curing agentsas additional reactive components in the treating baths.

It is another object of this invention to provide a process forimparting to hydrophobic materials the property of readily dissipatingelectrostatic charges normally formed thereon.

It is a further object of this invention to provide a durable finish ona synthetic hydrophobic material which enables the materials to retainmoisture and to possess a high degree of conductance.

It is still another object of this invention to provide a shapedstructure of synthetic material in which the accumulation of staticelectrical charges is elfectively eliminated due to the presence of anantistatic finish thereon, which finish is durable and thus not readilyremoved by repeated launderings and dry cleanings, and which finish doesnot impair the properties of the shaped structure with regard to itsappearance, hand, color, strength, abrasion-resistance, and the like.

Another object of this invention is to provide a process for improvingthe afiinity of hydrophobic synthetic materials, including polyolefinfibers, for acid dyestuffs.

It is also a further object of this invention to provide a process forimproving the aflinity of cellulosic materials and materials containingcellulosic fibers for acid dyestuffs, and the product thus formed.

It is a further object of this invention to provide an ion-exchangeresin and, further, a process for making the aforesaid resin.

In attaining the objects of this invention, one feature resides incontacting the material whose properties are to be modified with asolution, dispersion, or emulsion containing a sufiicient amount of amonomer of the in- R, R R are members selected from the group consistingof hydrogen and lower alkyl, and

R is an alkylene radical having from 2 to 3 carbon atoms,

X and Y are divalent organic radicals,

n is an integer selected from the group consisting of and 1, and

m is an integer from 3-50 inclusive.

While reference is made to the lower alkyl radicals, good results areobtained when the length of the carbon chain is from 1 to 6 carbons, andbest results are obtained when the lower alkyl radical has from 1 to 4carbon atoms. While compounds wherein R, R and R may have more than 6carbon atoms will perform satisfactorily, it is difficult to obtain suchcompounds commercially at this time.

The preparation of compounds wherein n equals 0, which are among thepreferred compounds for the present invention, is discussed in copendingapplication Ser. No. 94,720 filed Mar. 10, 1961, now U.S. Pat. No.3,197,463, and the disclosure of said application relating to thecompounds and to the preparation thereof is expressly incorporatedherein. Compounds wherein n equals 1, and X and/ or Y are defined by theradical OCOR* wherein R is a low molecular weight, aliphatic hydrocarbonradical, as disclosed in U.S. Pat. 2,596,200, and all references tothese compounds set forth in the aforesaid patent are incorporatedherein. For the purposes of the present invention the divalent organicradicals X and Y in the above formula may also include the followinggroups: -OCOR OSO;R, SO R,

-NHS0 R and the like.

Examples of compounds wherein X and Y are present in the formula (n=1)and have the aforesaid definitions are as follows:

(1) -OCOR products of reaction of imines with his acrylates, bismethacrylates and his crotonates of polyoxyalkylene glycols, asdescribed in U.S. Pat. 2,596,200.

(2) -OS0 R products of reaction of imines and diesters ofpolyoxyalkylene glycols with substituted and unsubstituted vinylsulfonic acids.

(3) --SO,R'-; products of reaction of imines with his vinyl sulfonyl orwith his haloalkyl sulfonyl compounds.

(4) NHCOR*-; products of reaction of imines with bis acrylamides,methacrylamides, and crotonamides, which are prepared by acylation ofpolyoxyalkylene diamines with carboxylic acid chlorides.

(5) -NHSOgR products of reaction of imines with his acrylamides,methacrylamides, and crotonamides, which are prepared by acylation ofpolyoxyalkylene diamines with sulfonyl chlorides.

Other definitions of --X and Y, wherein the compounds of the aboveformula will perform satisfactorily will be readily apparent and thus,the nature of the divalent organic groups -X and Y-- is not critical forthe purpose of the invention, although aliphatic divalent organic groupsare preferred.

Compounds of the above formula polymerize on heating to form the novelcross-linked polymeric products on the synthetic hydrophobic materials,which products are capable of retaining moisture and possess a highdegree of conductance.

The essentially monomeric compounds are applied in the form of asolution, emulsion, or dispersion, and the polymerization andinsolubilization thereof occur in situ on the treated material.

For the specific purpose of improving the properties of textilematerials manufactured from hydrophobic fibers, and preventing theaccumulation of static electrical charges thereon, the monomericcompounds of the aforesaid generic formula are applied from solution,dispersion, or emulsion, by impregnation, coating, spraying, or by otherknown methods, and the treated textile is then reacted to achievepolymerization and insolubilization of the compound applied. The amountof the monomer required to impart satisfactory properties, and, morespecifically, durable antistatic properties, is preferably from between0.2% to 10%, based on the weight of the textile. It will be appreciatedthat while more than 10% of the agent can be applied, no appreciableimprovements are to be noted, and, in fact, the polymerized product mayhave undesirable properties, such as tackiness, when present inexcessive amounts. After application of the antistatic agent, thetextile is preferably heated to accelerate the polymerization process.While the reaction proceeds slowly at room temperature, its rateincreases with a corresponding increase in the temperature.

If desired, rapid reaction can be achieved even at room temperature orbelow, by the addition of known acidic or acid-forming, catalysts oralkylating agents which greatly accelerate the polymerization reactionand insolubilization of the monomer. Acid or acid-forming catalysts arenumerous and may include non-volatile mineral acids, such as Hhydrochlorides, sulfates, nitrates, etc., of weak organic bases;chlorides and nitrates of magnesium and zinc; acid sulfates andphosphates of alkali metal; and other suitable compounds. Generallyspeaking, the amount of the compound and the reaction conditionsresulting in optimum properties and performance of the treated materialdepend to a considerable extent on the chemical and physical structureof the hydrophobic substrate employed, and can be readily determined.The amount of polymer remaining in the finished product is generallybetween 50 and of the amount applied, and a polymer content of 0.1% to10% in the finished product, based upon the weight of the materialtreated, is preferred.

Included among the synthetic hydrophobic materials which exhibitimproved properties when treated according to the process of the presentinvention are polyamide fibers (commonly referred to as nylon),polyester fibers (which include those sold under the trademark Dacron byE. I. du Pont de Nemours & 00.), polyolefin fibers, acrylic fibers,acrylonitrile fibers (which include those sold under the trademark Orionby B. I. du Pont de Nemours & (30.), cellulose triacetate fibers,polyvinyl chloride fibers, polyethyleneterephthalate yarns, and thelike. Such hydrophobic structures are more fully defined in U.S. Patent2,982,751 and the definition thereof is incorporated herein byreference. Mixtures or blends of hydrophobic fibers with natural fibersalso exhibit greatly improved properties when treated according to theprocess of the present invention and, in some instances, highlydesirable results are achieved by employing the process tosimultaneously impart antistatic properties to the synthetic hydrophobicfiber component and other desirable properties, such as enhanceddyeability and dimensional stability, to the natural fiber component,such as the cellulosic fiber component. Thus, when a polyester-woolblend fabric is treated by the process of the invention, the end productis rendered durably antistatic and dimensionally stable. When apolyester-cellulose blend fabric is treated by the process of theinvention, durable antistatic properties are imparted to the polyesterportion of the fabric, while dimensional stability and increaseddyeability with acid dyes are achieved with respect to the cellulosicportion of the fabric.

When hydrophilic substrates such as cellulose or those containingcellulosic polymers, including cotton, rayon, paper, wood, linen, etc.,are treated in accordance with the invention, the monomer is convertedto the polymer which, it is believed, becomes attached to the cellulosemolecules by chemical bonds and enormously increases the dyeability ofthe cellulosic substrate with acid dyes. However, applicant does notwish to be bound by any theory as to why the unexpected results areobtained.

Furthermore, the polymerization reaction of the monomers can be carriedout in bulk, independently of the presence of any substrate, and thepolymerization products which are formed have utility as ion-exchangematerials in other processes, when prepared either in the absence of asubstrate or in the presence of an inert carrier such as silica gel.

The elfectivness of the new finishes on synthetic hydro phobic materialsis evaluated by known test procedures. For example, resistivity of anuntreated hydrophobic material is generally extremely high and, in thecase of fabrics manufactured from hydrophobic fibers, it is known that aspecific area resistivity higher than ohms at 40% relative humidityindicates a high tendency to the accumulation of static charges. Testmethods for measuring resistivity in textiles are described in severalpublications, including the Technical Manual of the American Associationfor Textile Chemists and Colorists, vol. 35, pp. 138- 139. Method Nos.Standard 761959 (Fabrics) and Tentative 84-1955 (Yarns). The resistivityresults reported in the following examples were obtained by the testmethods cited above.

The resistance of the finish to laundering and dry cleaning wasevaluated by measuring the resistivity of the treated samples bystandard methods after repeated washings or dry cleanings. The followingexamples are merely for 2 minutes at 300 F. and rinsed. The fabric sotreated had a specific area resistivity (SAR) of 5X10 ohms (at 70 F. and40% RH as specified in the test method used), whereas the untreatedfabric had a specific area resistivity higher than 10 ohms. Even after 5machine launderings at 140 F., the treated fabric had a specific arearesistivity (SAR) of 3 X 10 ohms, showing even less tendency to staticaccumulation than fabrics woven from hydrophilic fibers such as cottonand rayon fabrics which exhibit a SAR of the order of 10 ohms.

EXAMPLE II The procedure of Example I was repeated, except that 20 gramsper liter of magnesium chloride were added to the treating solution. TheSAR of the treated fabric was 1.1 X 10 ohms after the heating step, 2.410 ohms after one laundering and 9X 10 ohms after 5 machine launderingsat 140 F.

EXAMPLE III The procedure of Example I was repeated, except that thefabric used was pretreated with a 1% aqueous solution of sulfuric acidand dried prior to impregnation with the monomer solution. Afterimpregnation, the treated fabric was dried at 220 F. and allowed tostand at room temperature for 24 hours. The SAR of this treated fabricwas 4x10 ohms. After one laundering it was 1.2 10 ohms and after 5 drycleaning treatments it was 9 10 ohms.

EXAMPLE IV Four swatches of undyed bleached Dacron polyester fabric wereimpregnated on a laboratory padder with an aqueous solution containinggrams per liter of the following monomer:

at a wet pickup of 35% thus yielding 1.75% of the monomer on the weightof the fabric. The swatches were dried at 250 F. and then thepolymerization reaction of the monomer on the fabric was allowed to takeplace under varying conditions of time and temperature. The samples werethen rinsed. The SAR values obtained on these samples (measured at 40%RH and 70 F.) after treatment, and after various laundering and drycleaning procedures, are tabulated below:

illustrative of the invention, and are not to be considered limiting thescope of the invention in any manner. All parts are by weight unlessotherwise specified.

EXAMPLE I A swatch of undyed, bleached talfeta fabric woven from 100%Dacron polyester yarn was impregnated on a laboratory padder with anaqueous solution containing grams per liter of the following monomer,

at a wet pickup of 33%, thus depositing 2% monomer on the weight of thefabric. The sample was dried, heated It is apparent from these resultsthat the insolubilization reaction proceeds very slowly at roomtemperature and that the finish is removed in laundering from sample 1.Sufficient time at room temperature (sample 2), or a short time atelevated temperature (samples 3 and 4) cause the polymerization reactionto proceed to an adequate extent, thereby insolubilizing the finish andmaking it resistant to laundering and dry cleaning. The followingExample V will demonstrate the accelerating effect of magnesium chlorideupon the polymerization reaction.

EXAMPLE V The procedure of Example IV was repeated, except that 50 gramsper liter of magnesium chloride hexahydrate were added to the treatingsolution. The SAR values obtained on the samples so treated aretabulated below:

TABLE 2 SAR, ohms As Temperature treated Reaction Sample No. timeUntreated fabric. 5 1 hr It is apparent that outstanding resistance tostatic accumulation can be obtained by these processes, and that thefinished fabric product maintains its antistatic properties even afterrepeated laundering. It has also been found that the antistaticproperties of the finished fabric are maintained even after dry cleaningtreatments.

EXAMPLE VI TABLE 3 SAR, ohms Reaction time at After 5 Sample N 0. 310 F.As treated laundorings Untreated fabric 10 9 30 seconds 1. 0X10" 10"10"... 2minutes 7.1X10 5X10 ll Bminutes 3.3Xl0 6X10 It is apparent thatthe 2 minute reaction time is sufiicient to achieve insolubilization anddurability of the finish. The reaction can be accelerated by theaddition of acidic or acid-forming catalysts to the treating solution.

EXAMPLE VII Similar results were obtained when the procedure of ExamplesIV, V, and VI were repeated using the compound EXAMPLE VIII CH CH:

TABLE 4 Grams liter Magnesium Zinc Compound chloride fiuorohorateSolution:

The wet pickup for this fabric under the padding conditions used wasapproximately 80%. The padded samples were dried, then divided inseveral portions in order to establish the optimum reaction conditions.Portions of each sample were reacted under the following conditions;

(a) at room temperature for 24 hours (b) at 280 for 3 minutes (c) at 300for 5 minutes After the reaction period, the samples were rinsed. Allsamples so treated exhibited excellent antistatic properties (SAR of theorder of 10 ohms or lower at 40% RH and F.) and the antistaticproperties were still excellent after 30 machine launderings at 140 F.

EXAMPLE IX A swatch of undyed bleached polyester fabric was treated on alaboratory padder with an aqueous solution containing 50 grams per literof the compound:

at 35% wet pickup. The treated fabric sample was dried, then heated for5 minutes at 300 F. to induce polymerization of the monomer applied, andrinsed. The SAR of the cured fabric was 1.6 l0 ohms as treated, and 6X10after laundering at 140 F.

EXAMPLE X Samples of a polyester/wool fabric woven from yarns consistingof 55% polyester fiber and 45% wool fiber were treated with the compoundof the formula shown in Example I from aqueous solutions containing 20,40, 60, and grams per liter of the compound and containing 5, 10, 15,and 20 grams per liter respectively of magnesium chloride hexahydrate.The padded samples were dried and cured for 5 minutes at 300 F. andrinsed. They were then compared with the untreated control fabric intests for tendency to accumulate static electricity (SAR value-testmethod Lo.) and for dimensional stability (test method, Technical Manualof the American Association of Textile Chemists and Colorists, vol. 35,p. 133, test No. 1).

The results tabulated above demonstrate the outstanding combination ofproperties, namely antistatic properties and dimensional stability,which can be achieved on polyester/wool blend fabrics by the use of thenew process. Treatment of a 70/30 polyester/wool blend fabric alsoyielded a product of excellent properties.

EXAMPLE XI A fabric woven from 100% polypropylene spun yarn was treatedon a laboratory padder with an aqueous solution containing 100grams/liter of the compound represented by the formula shown in ExampleVIII and 20 grams/liter of magnesium chloride hexahydrate. The wetpickup was 60%, and the amount of monomer deposited on the fabric was 6%based on the weight of the fabric. The treated fabric was heated for 30minutes at 200 F. and rinsed. The finished fabric exhibited excellentantistatic properties. When the fabric was dyed by conventionalprocedures with acid dyestuffs (including Acid Red 106, Acid Blue 23,and the like), the polymers formed on the fabric acquired a deep shadewhich was resistant to washing. Both antistatic properties and affinityfor acid dyestuffs were maintained through repeated launderings and drycleanings. Untreated polypropylene exhibits an extreme tendency tostatic accumulation and no affinity for acid dyes.

EXAMPLE XII A bleached, desized cotton fabric was padded with a solutioncontaining 35 grams/ liter of the compound represented by the formulashown in Example VIII and g./ liter of zinc fiuoroborate, dried, curedfor 30 minutes at 200 F. and rinsed. The cotton fabric so treated wasdyed a deep bright shade with the following dyestuffs: Acid Yellow 23,Acid Blue 23, Acid Yellow 63, Acid Violet 34, and Acid Orange 74. Thecolor imparted was fast to washing, and treated fabric which had beenwashed even repeatedly, maintained aflinity for the acid dyes, whileuntreated cotton fabric could not be dyed under comparable conditions.

The dyestuffs referred to in the foregoing examples are identified bythe following numbers in the Color Index, American Association ofTextile Chemists & Colorists, second edition, 1956:

Acid Yellow 23-New C.I. No. 19140 Acid Blue 23-New C.I. No. 61125 AcidYellow 63-New C.I. No. 13095 Acid Violet 34-New C.I. No. 61710 AcidOrange 74New C.I. No. 18745 Acid Red 106-New (LI. No. 18110 Applicationof the antistatic finish of the present invention may be made to anyform of the shaped structure including foams, fabric, yarn, tow, staple,films, plastic sheeting, and the like.

Many modifications of the above examples will be apparent to thoseskilled in the art without departing from the basic concept of theinvention.

I claim:

1. A material selected from the group consisting of a synthetic,hydrophobic material unblended with proteinaceous fibers, a cellulosictextile material, and a blend of a synthetic, hydrophobic textilematerial and a cellulosic textile material, said material having afinish thereon of a polymerized and insolubilized monomer represented bythe formula R, R and R are hydrogen or lower alkyl, R is an alkyleneradical having 2 or 3 carbon atoms,

and m is an integer from 3 to 50, inclusive, or (2) CH -CH N-(EH-OHCOO-(CH CH OM- CH, CH;

oH-cm CHzCH20CoCH2 l HN 2. A product as set forth in claim 1 whereinsaid material is a synthetic, hydrophobic textile material.

3. A product as set forth in claim 1 wherein said material is in filmform.

4. A product as set forth in claim 2 wherein said textile is formed frompolypropylene.

5. A product as set forth in claim 2 wherein said textile is formed froma polymer of acrylonitrile.

6. A product as set forth in claim 2 wherein said textile is formed froma polyamide.

7. A product as set forth in claim 2 wherein said textile is formed froma polyester.

8. A product as set forth in claim 1 wherein said material is acellulosic textile material.

9. A product as set forth in claim 1 wherein said material is a blend ofa synthetic, hydrophobic textile and a cellulosic textile material.

10. A synthetic hydrophobic material unblended with proteinaceousfibers, as set forth in claim 1 having a finish thereon of a polymerizedand insolubilized monomer of the formula said finish impartingantistatic properties to said synthetic hydrophobic material.

11. A synthetic hydrophobic material unblended with proteinaceousfibers, as set forth in claim 1 having a finish thereon of a polymerizedtnd insolubilized monomer of the formula said finish impartingantistatic properties to said synthetic hydrophobic material.

12. A synthetic hydrophobic material unblended with proteinaceousfibers, as set forth in claim 1 having a finish thereon of a polymerizedand insolubilized monomer of the formula said finish impartingantistatic properties to said synthetic hydrophobic material.

13. A synthetic hydrophobic material unblended with proteinaceousfibers, as set forth in claim 1 having a finish thereon of a polymerizedand insolubilized monomer of the formula said finish impartingantistatic properties to said synthetic hydrophobic material.

14. A synthetic hydrophobic material unblended with proteinaceousfibers, as set 'forth in claim 1 having a finish thereon of apolymerized and insolubilized monomer of the formula OHS-CH N-oH-oH,0o

H; CH:

CH-CHs (ornomoJn-omon o o0 oIncH-N CH3 on, said finish impartingantistatic properties to said synthetic hydrophobic material.

15. A process for imparting desirable properties to a material selectedfrom the group consisting of a synthetic hydrophobic material unblendedwith proteinaceous fibers, a cellulosic textile material and a blend ofa synthetic hydrophobic textile material and a cellulosic textilematerial comprising applying to said material in an amount sufficient toimpart said properties of a monomer represented wherein R, R and R arehydrogen or lower alkyl, R is an alkylene radical having 2 or 3 carbonatoms,

and m is an integer from 3 to 50, inclusive, or

GH-CH3 CH CHZO C O CHgCH-N CH3 CH;

polymerizing and insolubilizing said monomer, in situ, on said material.

16. The process as set forth in claim wherein said material is asynthetic hydrophobic textile material unblended with proteinaceousfibers.

17. The process as set forth in claim 15 wherein said synthetichydrophobic material is in film form.

18. The process as set forth in claim 15 wherein the amount of monomerapplied to said material is from 0.2 to 10% by weight of said material.

19. A process of increasing the affinity for acid dyestuffs of acellulosic textile material comprising applying to said textile materiala suflicient amount of a monomer having the formula R, R and R arehydrogen or lower alkyl, R is an alkylene radical having 2 or 3 carbonatoms,

and polymerizing and insolubilizing said monomer, in situ, on saidtextile material.

References Cited UNITED STATES PATENTS 1/ 1965 Tesoro. 7/1965 Tesoro etal.

GEORGE F. LESMES, Primary Examiner J. CANNON, Assistant Examiner US. Cl.X.R.

8ll5.5, 116.2,100, 168, 54.2, 117-155, 143, 139.5, 138.8; 2602.l, 9, 13,857, 860, 897, 898, 899

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated August 5,1971 Patent No. 3, 597, 146

lnventofls) Giuliana C, Tesoro It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

In Column 9, beginning at line 66 in formula (1) the structure should beas follows:

Signed and sealed this 25th day of June 197M.

(SEAL) Attesting Officer USCOMM-DC 60376-P69 )RM PO-105O [10-69) a u sGCIVERNHENY PRINYING ornc: I969 0-4554

